Thread-cutting die.



Patented Dec. 24, I90].

J. GJSPEAB.

THREAD CUTTING DIE.

(Applicafiufi filed June 21, 1900.

(No llodel.)

MH//// M /7 WTNEtgnL'ai N0. 689,658. Patented Dec. 24, I901. .J. G.SPEAR.

' "THREAD CUTTING DIE.

. (Application filed June 21, 1900.)

(No Model.)

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Patented Dec. 24, l90l. J. G. SPEAR. THREAD CUTTING ma.

(Application filed June 21, 1900..)

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(No Model.)

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I I I I THE NORRIS PETERS CO FNOTO LIYHO WASH NDTGN D l \MTNEEEEs U IT DSTATES PATENT OFFICE.

JOHN G. SPEAR, OF VVINSTED, CONNECTICUT.

THREAD-CUTTING DIE.

SPECIFICATION forming part of Letters Patent No. 689,658, dated December24., 1901.

' Application filed June 21, 1900. S ri l No. 21,087. (No model.)

To all whom it may concern.-

Be it known that I, JOHN G. SPEAR, of Winsted, in the county ofLitchfield and State of Connecticut, have invented certain new anduseful Improvements in Thread-C utting Dies, of which the following is aspecification.

This invention has relation to rotary threadcutting dies, such as areemployed on boltcutting machines or on engine-lathes.

The object of the invention is to provide certain improvements in themechanism of the class referred to for moving the chasercutters into apredetermined operative position and securing them to operate on thework.

To this end the invention consists of a thread-cutting die comprising aplurality of chaser-cutters and a ring normally rotating with thecutters and having an'internal camsurface for engaging the ends of saidcutters and moving them into operative relation to the Work, and it alsoconsists in novel means for effecting a movement of the said ringrelatively to the cutters.

It further consists of mechanism capable of fine adjustment for lockingthe ring in a predetermined position with relation to the cutters andalso devices for effecting the release of the cam-ring to permit itsassuming its normal inoperative position.

Referring to the drawings, which represent the invention, Figure 1illustrates in perspective View a portion of an en gine-lathe to whichthe invention is shown as attached. Fig. 2

T represents a front elevation of the die, a por- 5 represents a frontelevation of the die Withthe front plate removed. 7 Fig. 6 represents inperspective view the cam-ring. Fig. '7 is an enlarged View of theadjustable catch attached to the cam-ring and adapted to be engaged by alatch or look on the die-body or cutter-support. Figs. 8 and 9illustrate the invention as constituting a portion of the spindle of abolt-cutting machine.

The invention comprises a die-body 20, having radial grooves 21 toreceive the chasercutters 22. The die-body may be formed, as in Fig. 4,with the central aperture 23 and secured by bolts 24 to a collar 25,adapted portion of the spindle itself, as illustrated in Fig. 9, whereit is shown as forming a portion of the bolt-cutting machine. In thelastmentioned case it obviates the long overhang that is essential wherea body is attached to the spindle by means of a collar. The-ends of thechaser-cutters project beyond the periphery of the front portion of thebody or support, and said cutters are normally held in inoperativeposition by powerful leaf-springs 26, which are arrangedin slots in thefront face of the die-body and have-their ends projecting into apertures27 in the chaser-cutters. It will be observed that the inner walls ofthe slots 28 in the (lie-body are so curved that said springs are freeto have their ends move inward, while at the same time their middleportions fit snugly between the opposing walls of the slots.

Rotatively mounted upon the periphery of the die-body is a cam-ring29,whose back face rests againsta flange 30 on the die-body. The saidcam-ring, as well asthe chasers, is held against movement longitudinallyof the axis of rotation of the die by means of a front plate 3l,which isapertured at its center, as shown in Fig. 2, and is secured to the frontface of the die-body by screws 32. The camring is provided with aplurality of internal notches 33, into which the ends of thechasercutters project. The walls 34 of said notches are inclined to formcam-surfaces,which when the cam-ring is rotated with relation to thecutter-body cause the chaser-cutters to be wedged in toward the axis ofrotation and into engagement with the work. The walls 34 of said notchesprovide stops against which the side edges adjacent the outer ends ofthe chaser-cutters may engage to limit the rotation of the cam-ringrelatively to the die-body. The ring and the chaser-cutters lie in thesame planes, and the walls 34 form abutments against which the ends ofsaid cutters rest,wl1e reby they are held rigidly against the work whenoperating.

In order to effect a movement of the camring relatively to the die-bodyto cause a radial inward movement of the chaser-cutters, I employfriction mechanism, consisting of a rin 35 which loosel encircles thecam-rin b 9 b IOO and is provided with a resilient stem or standard 36,supported at its lower end in the bed of the lathe or hung from abracket, as in Figs. 8 and 9. To the upper portion of the ring isattached a handle 37, by means of which the ring may be swung to oneside or the other relatively to the cam-ring, the resilient standard 36returning the friction-ring to inoperative position after it is releasedby the operator. The cam-ring 29 is formed with a peripheral V-shapedgroove 38, and to the inside of the friction-ring is attached asegmental friction-shoe 39 by means of screws 40, the said shoe beingsubstantially wedge-shaped in section, as shown.

Assuming that the die-body and the camring are rotating in the directionof the arrow in Fig. 5, it willbe seen that byswinging the friction-ringto the left the segmental friction-shoe may be brought into frictionalengagement with the cam-ring to retard its rotation, whereby the ends ofthe chaser-cutters ride against the cam-walls 34 of the notches 33 andare forced radially inward. Upon releasing the pressure of the shoeagainst the cam-ring the springs 26 force the chaser-cutters outwardwith a pressure sufficient to cause their ends to return the camring toitsinitial inoperative position. Therefore I provide mechanism forlocking the cam-ring after it has been moved into operative position.Said locking mechanism comprises a latch on the die-bod y and a catchadjustably secured to the cam-ring. The latch consists of a bolt 41,mounted in a radial slot in the face of the die-body and adapted to bethrust outward by tensionsprings 42,placed in sockets, as shown in Fig.4. The catch consists of a block 43,placed in a recess in the innersurface of the cam-ring and having a socket 44 to receive the bolt 41.The sides of the block are inclined or beveled in the same direction,and said block is held between two wedges 45 45. Each of said wedges hasa lug 46,with a threaded aperture to receive a screw 47, whose ends arejournaled in lugs in the cam-ring. The outer ends of the screws areprovided with slots to receive a tool by which they may be rotated. Byadjusting said wedges through the medium of the screws 47 the block 43may be adjusted about the axis of the cam-ring. From this constructionit is apparent that when the cam-ring is retarded by the frictiondevice, previously referred to, the bolt 41 slips into the socket 44 andthe cam-ring and die-body are locked together. To release the latch orbolt 41 from the catch, a pin 48 is passed radially through the block 43and also through an elongated slot 49 in the cam-ring,and when the latchis engaged with the catch the said pin projects beyond the bottomsurface of the groove in the cam-ring. Therefore to the inner surface ofthe friction-ring I attach a shoe 50 by means of screws 51, whereby thering may be moved to the right in Fig. 5 to cause said shoe to engagethe pin and thrust the bolt out from the socket in the block, andthereby permit the springs 26 to force the chaser-cutters outward andrestore the camring to an inoperative position. The shoe 50 is narrowerthan the groove in the cam-ring, as shown, and at its ends it is beveledto easily ride over the projecting end of the pin. WVhen thefriction-ring is in a central position, both shoes are inoperative, andhence said friction-ring may be swung to one side or the other to causeeither of the shoes to perform its function, as occasion may require.

I have referred to the shoe-carrying memher as a friction-ring, but itis apparent that; the shape of the said member is immaterial, and, infact, the two shoes may be mounted on separate members if desired,although for all general purposes the construction which I haveillustrated is the best that has occurred to me.

Having thus explained the nature of the invention and described a way ofconstructing and using the same, although without attempting to setforth all of the forms in which it may be made or all of the modes ofits use, I declare that what I claim is 1.Athread-cuttingdiecomprisingafreelyrotatable body, chaser cutterssupported thereby and rotatable therewith, an annular member supportedon said body to rotate therewith but having a limited rotative movementrelatively thereto, said member being operatively arranged with respectto said chaser-cutters to effect a movement of the latter to operativeposition when said annular member is retarded in rotation, an automaticlock for holding said member in its retarded position, and a frictiondevice for retarding the rotation of said member, said friction devicebeing normally disengaged from said member and being wedge-shaped toenter a complemental groove in said member.

2. Athread-cuttingdiecomprisingafreelyrotatable body, chaser cutterssupported thereby and rotatable therewith, an annular member supportedon said body to rotate therewith but having a limited rotative movementrelatively thereto, said member being operatively arranged with respectto said chaser-cu tters to effect a movement of the latter to operativeposition when said annular member is retarded in rotation, a lock forholding said member in its retarded position, and oppositely-positionedmeans for alter nately retarding the rotation of said member andreleasing it from said lock.

3. A rotary thread-cutting die comprising a rotary body, chaser-cutterssupported by said body, a cam-ring rotatably supported on said body foreffecting a movement of said chaser-cutters to operative position, andhaving a circumferential V-shaped groove, a frica rotary body,chaser-cutters supported by and rotatable with said body, a cam-ringrotatably supported on said body for effecting a movement of saidchaser-cutters to operative position, an automatic lock for holding thecam-ring in operative position, operativelypositioned means forretarding the cam-ring to cause it to assume an operative position,operatively-positioned means forreleasing the lock, means forautomatically maintaining said retarding means and said releasing meansinoperative except when positively actuated.

5. A thread-cuttin g die comprising a rotary body, chaser-c utterssupported by said body, an operative ring rotatably supported on saidbody for effecting a movement of said chasercutters to operativeposition, a lock for holding the ring in operative position, and anupright spring-tensioned member having means for retarding the rotationof the ring, to cause it to assume an operative position and also havingoppositely-positioned means for disengaging the lock from the ringtopermit it to assume an inoperative position.

6. A thread-cutting die comprising a body, chaser-cutters supported bysaid body, a ring rotatably supported on said body for effect-- ing amovement of said chaser-cutters to operative position, a lock forholding the ring in operative position, a laterallymovable nonrotaryring having a shoe for retarding the rotation of the ring and anoppositely-arranged shoe for disengaging the look from the said ring.

7. A threadcutting die having a body, chaser-cutters supported by saiddie, a ring having means for operating said chaser-cutters and rotatablewith relation to said body, a latch carried by the said body,acatch-block carried by the ring and wedging means for adjusting saidcatch-block about the axis of said ring.

8. A thread cutting die having a body,

chaser-cutters supported by said die, a ring having means for operatingsaid chaser-cutters and rotatable with relation to said body, a latchcarried by the said'body, a catch-block on said ring having obliqueends, and adj ustable Wedges engaging said ends for adjusting saidcatch-block.

9. A thread-cutting die comprising a unidirectionally rotatable body,chaser-cutters mounted on said body, mechanism for moving saidchaser-cutters into operative position, frictioumechanism for operatingthe cutter-moving mechanism, means for locking said lastmentionedmechanism when the chaser-cutters are in said last-mentioned position, adevice for releasing the said mechanism and causing said chaser-cuttersto be moved into inoperative position during the continued rotation ofsaid body, said friction mechanism and said device being located in thesame planes transverse to said threadcutting die.

10. Arotary thread-cutting die, comprising a rotary body, cutterssupported by and rotatable with said body, a ring carried by said bodybut movable relative thereto, and hav-- ing provision for engaging saidcutters to move the latter in one direction as the ring is turnedrelative to the body, frictional means for giving to said ring saidrelative movement, means for looking said ring in its operated position,and means for unlocking said ring, and springs arranged to oppose themovement of the cutters by the ring, whereby when the latter is unlockedthe springs will automatically return the cutters and through them thering to their initial position. r

In testimony whereof I have aflixed my sig nature in presence of twoWitnesses.

JOHN G. SPEAR.

